Pack logic cleanup

SVSim.UnitTests/Services/DbCardPoolProviderTests.cs

@@ -64,4 +64,85 @@ public class DbCardPoolProviderTests
 
         Assert.That(pool, Is.Empty);
     }
+
+    [Test]
+    public async Task GetPool_excludes_foil_cards()
+    {
+        using var factory = new SVSimTestFactory();
+        long nonFoilId, foilId;
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            // Pick the highest-Id card so that id+1 is guaranteed unoccupied.
+            nonFoilId = await db.Cards.OrderByDescending(c => c.Id).Select(c => c.Id).FirstAsync();
+            foilId = nonFoilId + 1;
+            var foilCard = new ShadowverseCardEntry
+            {
+                Id = foilId, Name = $"Card {foilId}", Rarity = Rarity.Bronze, IsFoil = true,
+            };
+            // Add directly to the Cards DbSet and set the FK via shadow property,
+            // avoiding nav-collection tracker conflicts.
+            db.Cards.Add(foilCard);
+            db.Entry(foilCard).Property("ShadowverseCardSetEntryId").CurrentValue = 10001;
+            await db.SaveChangesAsync();
+        }
+
+        using var scope2 = factory.Services.CreateScope();
+        var provider = scope2.ServiceProvider.GetRequiredService<ICardPoolProvider>();
+        var pool = provider.GetPool(new PackConfigEntry
+        {
+            Id = 10001, BasePackId = 10001,
+            PackCategory = PackCategory.None,
+        });
+
+        Assert.That(pool.Any(c => c.Id == nonFoilId), Is.True,  "non-foil must be in the pool");
+        Assert.That(pool.Any(c => c.Id == foilId),    Is.False, "foil must be excluded from the pool");
+    }
+
+    [Test]
+    public async Task TryGetFoilTwin_returns_the_id_plus_one_foil_when_present()
+    {
+        using var factory = new SVSimTestFactory();
+        long nonFoilId, foilId;
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            // Pick the highest-Id card so that id+1 is guaranteed unoccupied.
+            nonFoilId = await db.Cards.OrderByDescending(c => c.Id).Select(c => c.Id).FirstAsync();
+            foilId = nonFoilId + 1;
+            var foilCard = new ShadowverseCardEntry
+            {
+                Id = foilId, Name = $"Card {foilId}", Rarity = Rarity.Bronze, IsFoil = true,
+            };
+            db.Cards.Add(foilCard);
+            db.Entry(foilCard).Property("ShadowverseCardSetEntryId").CurrentValue = 10001;
+            await db.SaveChangesAsync();
+        }
+
+        using var scope2 = factory.Services.CreateScope();
+        var provider = scope2.ServiceProvider.GetRequiredService<ICardPoolProvider>();
+
+        var twin = provider.TryGetFoilTwin(nonFoilId);
+        Assert.That(twin, Is.Not.Null);
+        Assert.That(twin!.Id, Is.EqualTo(foilId));
+        Assert.That(twin.IsFoil, Is.True);
+    }
+
+    [Test]
+    public async Task TryGetFoilTwin_returns_null_when_no_foil_at_id_plus_one()
+    {
+        using var factory = new SVSimTestFactory();
+        long anyCardId;
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            anyCardId = await db.Cards.OrderBy(c => c.Id).Select(c => c.Id).FirstAsync();
+        }
+
+        using var scope2 = factory.Services.CreateScope();
+        var provider = scope2.ServiceProvider.GetRequiredService<ICardPoolProvider>();
+
+        Assert.That(provider.TryGetFoilTwin(anyCardId), Is.Null,
+            "no foil seeded at anyCardId+1, so TryGetFoilTwin must return null");
+    }
 }